In semiconductor manufacturing, gasses are used for a number of purposes, including the creation of plasma for etching a silicon or other wafer surface, ending reactions by introduction of inert gasses, etc. In the manufacturing chamber, a selected type of process gas is introduced into the process chamber as part of a specified step in the manufacturing process. A selected type of gas must be introduced within purity tolerances, at a specified flow rate and at a specified pressure and volume.
A number of different components of a gas transport system regulate the flow of gas to the process chamber. These components may include a mass flow controller, valves, regulators, filters, flow monitors, moisture monitors, gas purifiers, pressure sensors, diffusers, pressure transducers, among other components. In prior systems these components were arranged side by side, connected by a series of in line connectors. Each of the components is used for a specific function, such as a pair of valves connected between another component that allow isolation of that component. The components are connected in line along the horizontal flow path of the gas. Both the component and the connector add to the overall length of the entire gas transport system.
In semiconductor manufacturing, uniform standards that have been adopted to minimize the footprint required for a gas transport system. One method to reduce the length of the system is to have the gas flow into and out of the bottom of each component, rather than from the sides or top and bottom. In one current standard configuration, each of the components is mounted on a base plate. This base plate may have one of two configurations. In a first configuration, the base plate serves as nothing more than a support structure for gas flow devices. A separate system of blocks below each gas flow element provides a passage for fluid to flow from each element. An example of such as system is shown in U.S. Pat. No. 6,546,961, in which a number of passage blocks include passages from one gas flow component to another. A disadvantage of such systems is the added height requirement of the blocks. This may be a significant drawback, especially if the gas flow systems are going to be stacked. A second alternative is to provide passages in the base plate. In this manner, the individual gas flow elements may be connected using base plate without the need for additional connection blocks. This configuration has the added advantage that the height of the combined gas flow component and the base plate is not further raised by an underlying block.
In systems in which the gas flow components are used with a base plate, one gas flow component, the filter, may be designed such that it does not add to the length of the system. This would be done by using a block under one gas flow component in which the filter is incorporated. In the first configuration outlined above, the filter may be incorporated into one of the blocks. For example in U.S. Pat. No. 6,886,599 discloses a gas supply system including a number of gas supply components connected to each other through blocks positioned between each component and providing a passageway between each component for gas flow. The filter block component is a block extending between two gas flow components.
In the second configuration outlined above (in which the base includes fluid flow passageways) a block may also be included for the filtering of gas. This again allows elimination of one element from the length of the gas flow components. This comes at the cost of some added height to the system. One solution is to use a surface mount sandwich filter. For example, one surface mount filter is produced by TEM Filter Company and sold as product TEM 837125. This filter block is mounted between the base plate and a gas flow component. By placing the filter block under a valve or regulator, a separate filter substrate is not required, effectively shortening the filtration system and reducing the cost of the system. About an inch of height would be added to the component under which this filter block is inserted. This filtration block may be used with stainless steel filter media, high flow sintered nickel fiber media, or any other suitable media.
However one drawback of this filter block is the added height the block adds to the system. However manufacturing a shorter filter block has proved challenging. The primary challenge is designing a filter block that conforms to the industry standards, which set specifications for the systems. In some of these standards, the components have inlets and outflows that are essentially adjacent, requiring a filter block with similarly positioned passageways. It has proved difficult to manufacture a filter block that is both lower profile, has desired performance and conforms to the standardized configuration. It is an object of the present device to overcome these obstacles.